Such a launching and recovery device for personal watercraft is described in U.S. Pat. No. 5,245,940, to Rockwood, and in two United States Patents to Montgomery, U.S. Pat. Nos. 4,983,067 and 5,090,842. Each of these references describe, as is needed, the jetting of a post into the bottom ground beneath the water a sufficient distance to provide support and stability to a hoist which rides a support cradle for the watercraft along the vertical post, and able to pivot the cradle over a dock or seawall to allow the watercraft to be loaded or off-loaded, as well as to allow gear to be stowed in it, and for passengers to enter or leave. In typical arrangements--as for jet ski's of a weight of 250-450 pounds--, such vertical posts oftentimes are driven into the ground a distance of 5 feet or so, and then bolted, or otherwise secured, to the dock or seawall.
As these three prior references illustrate, their constructions each entail welding of a securing bracket to the post--as well as further welding to the post cylindrical tubes which traverse the upper post portion. As will be apparent, this"welding" requires a not insignificant amount of work to be done at the site where the lift device is to be installed.
As will also be apparent to those skilled in the art, such "welding" would, of necessity, have to be done at different points along the posts and may not be uniform from site-to-site, as the depth of water may vary from location to location, and as the dock or seawall may extend different distances above the water's surface from place to place. Thus, whereas one job might involve a post of a given length L.sub.1 and a "welding" thereon at a point P.sub.1 for one installation, another different installation is likely to require a different length of post L.sub.2 and a different positioning P.sub.2 where the "welding" is to be done.
Besides this, one skilled in the art would also be quick to see that for differently weighted personal watercraft, the vertical post may very well have to be driven further into the ground then for other constructions. Thus, where a personal watercraft of 800, or 1,000, or 1,200 pounds is to be launched and recovered, the vertical post would have to be jetted further into the bottom ground for the same degree of support and stability than if the cradle were only to be called upon to lift watercraft weighing the 250-450 pounds associated with many types of jet skis.
Taking all this together, it will therefore be seen that the manners of installation described in the Rockwood and Montgomery patents are not suited to a mass-market installation, but require specific parts, individual fabrications and, in general, "special orders" for one installation as compared to another. This makes the installation process both costly and time consuming and something which would be desirable to avoid. As those skilled in the art would appreciate, a more desirable situation would be one where the post, cylindrical tubes and bracket can be of a standardized size, then brought to the job site for erection, cut to the particular size required, and then bolted together there, without the need for "welding" or other unique fabrication techniques.